Tide Pools


On Puget Sound, the tide rises and falls twice a day...

The water along Puget Sound shores rises and falls, pulled by the gravitational forces of the moon and sun. A daily cycle along the Sound generally includes two unequal high tides and two unequal low tides.

Tidal Zones

Twice each day, the shore along Puget Sound is either underwater or open to air, rain, or the scorching sun. Beaches are composed of zones depending on the length of time they are underwater or exposed to air.

Tidal Zones & Habitats

  • Splash Zone
    Dry most of the time. Flooded only by spray or the biggest storm waves. Animals here must survive extreme heat, cold, and quick changes in salt content when it rains.
  • High Intertidal Zone
    Exposed and open to the air most of the time. Underwater only during the highest tides. Animals here are used to open air and many rely on tides to circulate food.
  • Mid Intertidal Zone
    Covered and uncovered by water twice a day. Moist most of the time. Temperature changes are less extreme here. Many animals in this zone depend on rising and falling tides to survive.
  • Subtidal, Lower Intertidal
    Underwater most of the time. Exposed only during extreme low tides. Fewest changes in temperature and salt content. Shelters the largest number of plants and animals. Many creatures here can also live in deeper water.

    Be Aware of Tides

    The shape of the Sound affects the tide as it moves through channels and inlets. In the Straight of Juan De Fuca, a 7.2 foot tide at Cape Flattery will reach Port Townsend 3 hours and forty minutes later and increase in magnitude to 7.9 feet. The tide will reach south Puget Sound 1 hour later and increase to 13.5 feet by the time the tide reaches Olympia. Extreme high tides of 18 feet have been recorded in Olympia.

    Tides Create Currents

    In Puget Sound, the tide rushes through narrow channels and around islands creating rapids and eddies like a whitewater river. It is important for boaters and beach explorers to know what the tide is doing. Some waters are not navigable at low tide. Some beaches may also be hazardous.

    Tidal Tips

    • Know the tides before visiting the beach. You can be stranded on a spit or in a cove if you aren't aware of a rising tide.
    • Avoid walking on logs or climbing bluffs. Loose logs can roll and bluffs can slide.
    • Watch out for boat wakes. Ferries and speed boats can create large waves.

    Related Topics

    Public Access, Where you can go to explore the beach.
    Tide Pools, Tide pool life and tips.

    Related Links One of the best online tide calculation sites -- and it prints out easy to read tide tables.

    Tidal Heights in Washington, British Columbia, & California. Tides predicted by Xtide, a program used to calculate the tides.

    Tides & Currents Education, NOAA. What makes the tides, tide predicting machines, and currents.

    National Weather Service, NOAA. Weather warnings, forecasts, current conditions, marine forecasts, and weather records.  

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